Ursolic acid inhibits the activation of smoothened-independent non-canonical hedgehog pathway in colorectal cancer by suppressing AKT signaling cascade.

It is being brought to light that smoothened (SMO)-independent non-canonical Hedgehog signaling is associated with the pathogenesis of various cancers. Ursolic acid (UA), a pentacyclic triterpenoid present in many medicinal herbs, manifests potent effectiveness against multiple malignancies including colorectal cancer (CRC). In our previous study, UA was found to protect against CRC in vitro by suppression of canonical Hedgehog signaling cascade. Here, the influence of UA on SMO-independent non-canonical Hedgehog signaling in CRC was investigated in the present study, which demonstrated that UA hampered the proliferation and migration, induced the apoptosis of HCT-116 cells with SMO gene knockdown, accompanied by the augmented expression of the suppressor of fused (SUFU), and lessened levels of MYC (c-Myc), glioma-associated oncogene (GLI1) and Sonic Hedgehog (SHH), and lowered phosphorylation of protein kinase B (PKB, AKT), suggesting that UA diminished non-canonical Hedgehog signal transduction in CRC. In HCT-116 xenograft tumor, UA ameliorated the symptoms, impeded the growth and caused the apoptosis of CRC, with heightened SUFU expression, and abated levels of MYC, GLI1, and SHH, and mitigated phosphorylation of AKT, indicating that UA down-regulated non-canonical Hedgehog signaling cascade in CRC. Taken together, UA may alleviate CRC by suppressing AKT signaling-dependent activation of SMO-independent non-canonical Hedgehog pathway.